I think Buff'll turn it around. The best you can do is give him support in this time. Like Bobby said, relapse is part of sobriety, it happens, I have family who've tripped time and time again, it took my father 14 years of failing to be sober before he finally became involved in my life again, and he's had two relapses since, so yes, it's a life time full of starting and failing. The stories you hear of someone being sober for decades... they happen, it's a wonderful thing, but for every success story there are ten more stories of people with interrupted streaks. Yes, some people use sobriety as a crutch, they use it to their advantage, but a majority of the time, it's a slip up, a wall of defense that has been shattered. We are man, flesh, and emotional beings, and we all become subdued by our desires and wants. I've done it before, not with drugs, but with alcohol, it's just a matter of weather or not you'll let addiction's weight squash you, or if you still have the fight in your soul to continue cleaning yourself up.
I think highly of Buff, he is, as my generation says, "based", and a genuinely good dude. Hope he picks up his saddle and rides that sober horse once again. He has it in him.